https://www.mips.com/develop/training-courses/mips-basic-training-course/
The MIPS64 Instruction Set v6.06
The microMIPS32 Instruction Set v6.05
https://s3-eu-west-1.amazonaws.com/downloads-mips/documents/MD00087-2B-MIPS64BIS-AFP-6.06.pdf
https://s3-eu-west-1.amazonaws.com/downloads-mips/documents/MD00582-2B-microMIPS32-AFP-6.05.pdf